Stars and the solar system. — Science STD 8 — Question

A person is in open space during a thunderstorm with no shelter (not even a tree) available nearby. Describe the safe position which he should take to protect himself from lightning. Why is this position considered safe?

Name the objects of historical significance found in Satpura National Park.

Why do brake pads of bicycles have to be replaced quite often?

Where do Rhizobium bacteria live? What is their function?

What is a polymer? Name the natural polymer of which cotton is made.

Name three useful products of coal.

Where is natural gas found? Why is natural gas called a clean fuel?

X and Y are the two types of cells. The cells X have a well-organized nucleus which is separated from the cytoplasm by the nuclear membrane on the other hand, cells Y do not have a real nucleus, their nuclear material is in direct contact with the cytoplasm.

1. What type of cells are (i) X, and (ii) Y?
2. Give one example each of cells like (i) X, and (ii) Y?

What is muscular force ? Give one example of muscular force.

Which of the following are kharif crops and which are rabi crops?
Wheat, Paddy, Gram, Maize, Mustard, Cotton, Soyabean, Linseed, Peas, Groundnut.